Strideshift instruction for transposing bits inside vector register

ABSTRACT

A processor includes a decode circuit to decode an instruction into a decoded instruction and an execution circuit to execute the decoded instruction to access a first bit of a first input vector located at a bit position indicated by an element of a second input vector, stride over bits of the first input vector using a stride to access bits of the first input vector that are located at a strided bit position with respect to the first bit of the first input vector, and store the first bit of the first input vector and the bits of the first input vector that are located at a strided bit position with respect to the first bit of the first input vector as consecutive bits in a destination vector.

TECHNICAL FIELD

Embodiments of the invention relate to the field of computer instructionset architecture; and more specifically, to a strideshift instructionfor transposing bits inside a vector register.

BACKGROUND

A processor or set of processors, executes instructions from aninstruction set, e.g., the instruction set architecture (ISA). Theinstruction set is the part of the computer architecture related toprogramming, and generally includes the native data types, instructions,register architecture, addressing modes, memory architecture, interruptand exception handling, and external input and output (I/O). It shouldbe noted that the term instruction as used herein generally refers to amacro-instruction (e.g., an instruction that is provided to theprocessor for execution), as opposed to a micro-instruction (e.g., aninstruction that results from a processor's decoder decodingmacro-instructions).

Modern processors often include instructions to provide operations thatare computationally intensive, but offer a high level of dataparallelism that can be exploited through an efficient implementationusing various data storage devices, such as for example,single-instruction multiple-data (SIMD) vector registers. In SIMDexecution, a single instruction operates on multiple data elementsconcurrently or simultaneously. This is typically implemented byextending the width of various resources such as registers andarithmetic logic units (ALUs), allowing them to hold and operate onmultiple data elements, respectively.

Determining the maximum and minimum values contained in a vector may beuseful for various purposes. One conventional technique for determiningthe maximum value contained in a vector extracts the upper half of thevector to another register, determines the maximum value using apairwise maxps instruction between two vectors, extracts the upper halfof the half-vector, and repeats this process until the maxps instructionis performed on just two elements. The minimum value contained in avector can be determined in similar manner. With this technique,determining the maximum and minimum values contained in a vector having16 elements requires executing a sequence of 16 instructions. Also, anumber of temporal registers are used to store intermediate results.

Another conventional technique for determining the maximum valuecontained in a vector uses an instruction that performs a squareall-to-all comparisons of the elements of the vector using a givencomparison operation (e.g., greater than or equal to) and stores theresult as bit values, where a bit value of binary ‘1’ indicatescomparison is true and binary ‘0’ indicates otherwise. This instructionallows the results of all comparisons of elements to each other to beobtained by a single instruction. Determining the minimum valuecontained in the vector may require executing another instruction thatperforms a square all-to-all comparison of the elements of the vectorusing a different comparison operation (e.g., less than or equal to)than the comparison operation used to determine the maximum value. Insome microarchitectures, the square all-to-all comparison instructioncan turn into a long sequence of micro-instructions and have highlatency. The conventional techniques for determining the maximum andminimum values contained in a vector may thus be inefficient.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a sequence of instructions beingexecuted to determine the maximum value contained in a vector, accordingto conventional techniques;

FIG. 2 is a block diagram illustrating a hardware processor and a memoryfor executing instructions, according to some embodiments;

FIG. 3 is a diagram illustrating a hardware processor that decodes andexecutes a strideshift instruction, according to some embodiments;

FIG. 4 is a diagram illustrating a sequence of instructions beingexecuted to determine the minimum values contained in a vector,according to some embodiments;

FIG. 5 is a diagram illustrating the result of executing a strideshiftinstruction that uses a cyclic addressing mode, according to someembodiments;

FIG. 6 is a flow diagram of a process for processing a strideshiftinstruction, according to some embodiments;

FIGS. 7A-7B are block diagrams illustrating a generic vector friendlyinstruction format and instruction templates thereof according toembodiments of the invention;

FIG. 7A is a block diagram illustrating a generic vector friendlyinstruction format and class A instruction templates thereof accordingto embodiments of the invention;

FIG. 7B is a block diagram illustrating the generic vector friendlyinstruction format and class B instruction templates thereof accordingto embodiments of the invention;

FIG. 8A is a block diagram illustrating an exemplary specific vectorfriendly instruction format according to embodiments of the invention;

FIG. 8B is a block diagram illustrating the fields of the specificvector friendly instruction format 800 that make up the full opcodefield 774 according to one embodiment of the invention;

FIG. 8C is a block diagram illustrating the fields of the specificvector friendly instruction format 800 that make up the register indexfield 744 according to one embodiment of the invention;

FIG. 8D is a block diagram illustrating the fields of the specificvector friendly instruction format 800 that make up the augmentationoperation field 750 according to one embodiment of the invention;

FIG. 9 is a block diagram of a register architecture 900 according toone embodiment of the invention;

FIG. 10A is a block diagram illustrating both an exemplary in-orderpipeline and an exemplary register renaming, out-of-orderissue/execution pipeline according to embodiments of the invention;

FIG. 10B is a block diagram illustrating both an exemplary embodiment ofan in-order architecture core and an exemplary register renaming,out-of-order issue/execution architecture core to be included in aprocessor according to embodiments of the invention;

FIGS. 11A-B illustrate a block diagram of a more specific exemplaryin-order core architecture, which core would be one of several logicblocks (including other cores of the same type and/or different types)in a chip;

FIG. 11A is a block diagram of a single processor core, along with itsconnection to the on-die interconnect network 1102 and with its localsubset of the Level 2 (L2) cache 1104, according to embodiments of theinvention;

FIG. 11B is an expanded view of part of the processor core in FIG. 11Aaccording to embodiments of the invention;

FIG. 12 is a block diagram of a processor 1200 that may have more thanone core, may have an integrated memory controller, and may haveintegrated graphics according to embodiments of the invention;

FIGS. 13-16 are block diagrams of exemplary computer architectures;

FIG. 13 shown a block diagram of a system in accordance with oneembodiment of the present invention;

FIG. 14 is a block diagram of a first more specific exemplary system inaccordance with an embodiment of the present invention;

FIG. 15 is a block diagram of a second more specific exemplary system inaccordance with an embodiment of the present invention;

FIG. 16 is a block diagram of a SoC in accordance with an embodiment ofthe present invention; and

FIG. 17 is a block diagram contrasting the use of a software instructionconverter to convert binary instructions in a source instruction set tobinary instructions in a target instruction set according to embodimentsof the invention.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth.However, it is understood that embodiments of the disclosure may bepracticed without these specific details. In other instances, well-knowncircuits, structures and techniques have not been shown in detail to notobscure the understanding of this description.

References in the specification to “one embodiment,” “an embodiment,”“an example embodiment,” etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment need not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

Determining the maximum and minimum values contained in a vector may beuseful for various purposes. One conventional technique for determiningthe maximum value contained in a vector extracts the upper half of thevector to another register, determines the maximum value using apairwise maxps instruction between two vectors, extracts the upper halfof the half-vector, and repeats this process until the maxps instructionis performed on just two elements. A sequence of instructions fordetermining the maximum value contained in a vector is as follows for avector zmm_index having 16 elements (KL=16).

vshuff3×4 zmm1, zmm_index, zmm_index, 238vmaxps zmm2, zmm1, zmm_indexvshuff3×4 zmm0, zmm2, zmm2, 85vmaxps zmm3, zmm0, zmm2vpshufd zmm4, zmm3, 78vmaxps zmm5, zmm3, zmm4vpshufd zmm6, amm5, 177vmaxps zmm_max, zmm5, zmm6

A similar sequence of instructions can be executed to determine theminimum value contained in a vector. A sequence of instructions fordetermining both the maximum and minimum values contained in a vector isas follows for a vector zmm_index having 16 elements (KL=16).

vshuff3×4 zmm12, zmm_index, zmm_index, 238vshuff3×4 zmm3, zmm_index, zmm_index, 238vmaxps zmm15, zmm12, zmm_indexvminps zmm6, zmm3, zmm_indexvshuff3×4 zmm14, zmm15, zmm15, 85vshuff3×4 zmm5, zmm6, zmm6, 85vmaxps zmm16, zmm14, zmm15vminps zmm7, zmm5, zmm6vpshufd zmm17, zmm16, 78vpshufd zmm8, zmm7, 78vmaxps zmm18, zmm16, zmm17vminps zmm9, zmm7, zmm8vpshufd zmm19, zmm18, 177vpshufd zmm10, zmm9, 177vmaxps zmm_max, zmm18, zmm19vminps zmm_min, zmm9, zmm10

With this technique, determining the maximum and minimum valuescontained in a vector having 16 elements requires executing 8 shuffleinstructions, 4 vminps instructions, and 4 vmaxps instructions, for atotal sequence of 16 instructions. Also, a number of temporal registersare used to store intermediate results.

Another conventional technique for determining the maximum valuecontained in a vector employs an instruction that performs a squareall-to-all comparison of the elements of the vector using a givencomparison operation (e.g., greater than or equal to) and stores theresult as bit values, where a bit value of binary ‘1’ indicatescomparison is true and binary ‘0’ indicates otherwise. This instructionallows the results of all comparisons of elements to each other to beobtained by a single instruction. Such an instruction may be referred toherein as a square all-to-all comparison instruction.

FIG. 1 is a diagram illustrating a sequence of instructions beingexecuted to determine the maximum value contained in a vector, accordingto conventional techniques. In the diagram, each vertical “column”represents the same lane of a vector register. The “offset” refers tothe position of an element. In this example, there are seven (KL=7)elements in a vector. The values and sizes of the vectors are providedby way of example for purposes of illustration. It should be understoodthat other values and sizes may be utilized. Zmm_index is the vectorcontaining the values from which the maximum value is to be determined.In this example, zmm_index contains the values 5, 7, 1, 1, 7, 3, and 1(in order from least significant bit (LSB) to most significant bit(MSB)). Executing the vconf_sqr_ge(zmm_index) instruction produceszmm_sqr_conf. The vconf_sqr_ge instruction performs a square all-to-allcomparison of the elements of a vector using a greater than or equal tocomparison operation. It can be seen from zmm_sqr_conf that the“column(s)” corresponding to the maximum value (there can be multiple ofthem, as in this example) contain all binary ‘1’s in the 7×7 matrix.Executing the vpcmpeq(zmm_sqr_conf, zmm_cmp) instruction compareszmm_sqr_conf to a pre-defined 7×7 matrix containing all binary ‘1’s(zmm_cmp) to produce k_mask_max, which contains binary ‘1’s in the bitposition(s) corresponding to the maximum value. Executing thevcompress(k_mask_max, zmm_index) instruction compresses zmm_index withk_mask_max to produce zmm_max, which contains the maximum value in itsLSB lane (the maximum value is 7 in this example).

The problem with determining the minimum value from zmm_sqr_conf (theresult of the vconf_sqr_ge instruction) is the existence of duplicatedminimum values. If there were no duplicated minimum values, then the“column” of zmm_sqr_conf corresponding to the minimum value wouldcontain all binary ‘0’s and it would be possible to extract the minimumvalue by comparing zmm_sqr_conf with a 7×7 matrix containing all binary‘0’s.

When there are duplicated minimum values, determining the minimum valuecontained in the vector may require performing another square all-to-allcomparison of the elements of the vector, but using a differentcomparison operation than the comparison operation used to determine themaximum value. The result may be compared to a pre-defined matrix toextract the minimum value. For example, a first technique may perform asquare all-to-all comparison of the elements of the vector using a lessthan or equal to comparison operation (e.g., using a vconf_sqr_leinstruction) and compare the result to a pre-defined matrix containingall binary ‘1’s. A second technique may perform a square all-to-allcomparison of the elements of the vector using a greater than comparisonoperation and compare the result to a pre-defined matrix containing allbinary ‘0’s. A sequence of instructions for determining the maximum andminimum values contained in a vector is as follows for a vectorzmm_index (using the first technique).

-   -   (1) zmm_sqr_vconf_ge=vconf_sqr_ge(zmm_index)    -   (2) k1=vpcmpeq(zmm_scr_vconf_ge, zmm_cmp)    -   (3) zmm_max=vcompress(k1, zmm_index)    -   (4) zmm_sqr_vconf_le=vconf_sqr_le(zmm_index)    -   (5) k2=vpcmpeq(zmm_sqr_vconf_le, zmm_cmp)    -   (6) zmm_min=vcompress(k2, zmm_index)

In some microarchitectures, a square all-to-all comparison instruction(e.g., vconf_sqr_ge and vconf_sqr_le) can turn into a long sequence ofmicro-instructions and have high latency. Depending on the number ofcomparators present in the microarchitecture, this technique fordetermining the maximum and minimum values contained in a vector can, insome situations, perform worse than the technique described above thatuse the shuffle and vmaxps/vminps instructions. The conventionaltechniques for determining the maximum and minimum values contained in avector may thus be inefficient.

Certain embodiments disclosed herein overcome the disadvantages of theconventional techniques by providing a strideshift instruction thatallows the maximum and minimum values contained in a vector to bedetermined based on the result of a single square all-to-all comparisoninstruction. The strideshift instruction can be used to transpose theresult of the square all-to-all comparison instruction with respect to amain diagonal (e.g., (0, 0)->(KL−1, KL−1). The transposed result can becompared with a pre-defined matrix to extract the minimum value. Withthe strideshift instruction (e.g., vstrideshift), both the maximum andminimum values contained in a vector (zmm_index) can be determined witha total of 6 instructions as follows:

-   -   (1) zmm_sqr_conf=vconf_sqr_ge(zmm_index)    -   (2) k1=vpcmpeq(zmm_sqr_conf, zmm_cmp)    -   (3) zmm_max=vcompress(k1, zmm_index)    -   (4) zmm_transposed=vstrideshift(zmm_sqr_conf)    -   (5) k2=vpcmpeq(zmm_transposed, zmm_cmp)    -   (6) zmm_min=vcompress(k2, zmm_index)

Compared to the sequence of instructions that determines the maximum andminimum values contained in a vector based on executing shuffle andvmaxps/vminps instructions, the above sequence of instructions thatincludes the strideshift instruction is shorter (6 instructions vs. 16instructions) and uses less number of temporal registers. Compared tothe sequence of instructions that determines the maximum and minimumvalues contained in a vector based on executing two square all-to-allcomparison instructions (e.g., vconf_sqr_ge and vconf_sqr_le), the abovesequence of instructions that includes the strideshift instruction mayhave better performance and lower latency depending on whether thesquare all-to-all comparison instruction or the strideshift instructionhas better performance characteristics on the underlyingmicroarchitecture.

FIG. 2 is a block diagram illustrating a hardware processor and a memoryfor executing instructions, according to some embodiments. Depictedhardware processor 100 includes a hardware decoder 102 (e.g., decodeunit or decode circuit) and a hardware execution unit 104 (e.g.,execution circuit). Depicted hardware processor 100 includes register(s)106. Registers 106 may include one or more registers to performoperations in, e.g., additionally or alternatively to access of (e.g.,load or store) data in memory 110. It should be noted that the figuresherein may not depict all data communication connections. One ofordinary skill in the art will appreciate that this is to not obscurecertain details in the figures. It should be noted that a double headedarrow in the figures may not require two-way communication. For example,it may indicate one-way communication (e.g., to or from that componentor device). Any or all combinations of communications paths may beutilized in certain embodiments herein.

Hardware decoder 102 may receive an instruction (e.g.,macro-instruction) and decode the instruction (e.g., intomicro-instructions and/or micro-operations). Execution unit 104 mayexecute the decoded instruction to perform one or more operations. Thedecoder 102 and the execution unit 104 may decode and execute any of theinstructions disclosed herein (e.g., strideshift instruction). Certainembodiments disclosed herein provide a strideshift instruction that canbe decoded and executed by the decoder 102 and execution unit 104,respectively. As will be described in additional detail below, thisinstruction may be used to more efficiently determine the maximum andminimum values contained in a vector compared to conventionaltechniques.

In one embodiment, a strideshift instruction has the followingdefinition:

VSTRIDE[C]SHIFT{B, W} dest{k1}, src1, src2, imm8 (KL, VL) = (64, 512),(32, 512) // where KL is the number of elements in thesource/destination vector and VL is the vector length N = VL/KL //granularity of the destination in bits: 8 or 16 (B, W) stride = imm8 //stride in bits 0...255 for (i = 0; i < KL; i++) {  // loop overi-elements of the destination    if (k1[i]) {       offset = src2[i] //starting position 0...255 for 8 bit granularity, 0...511 for 16 bit            //granularity       for (k = 0; k < N; k++) { //k is a bitposition in each i-element of the //destination          index =offset + k * stride          if (cyclic_addressing) //”C” letter inopcode of instruction             // store bit value from src1 to k-thbit in i-th element of destination             // (cyclic addressingmode)             dest[i * N + k] = src1[index & (VL − 1)]          else            //// if index is out of range, then zero destination bit            dest[i * N + k] = (index < VL) ? src1[index] : 0       }   }    else {  // zeroing mode       dest[i] = 0  // zero destinationbit if k1[i] == 0    } }In this instruction, {B, W} indicates the size of supported elements(e.g., byte (B) and word (W)) and {k1} indicates the write mask. In thisinstruction, KL is the number of elements in the destination vector(dest), VL is the number of bits in the destination vector, N is thenumber of bits in packed element of the destination vector, stride istaken as an immediate operand (or can be src3), src1 is the vector to betransposed, and src2 is the vector containing starting positions. In oneembodiment, operation of this instruction may be described as follows:take bits from src1 starting from the bit position indicated in src2[i]and going with the stride over bits in src1 (e.g., src1[index], whereindex=offset+k*stride). The N bits taken from src1 are stored asconsecutive bits in the i-th element of the destination vector (dest).Here, all vectors are addressed as one-dimensional arrays with VL bits.There are two possible addressing modes for src1. Cyclic addressing modeand range addressing mode. In cyclic addressing mode, when index reachesthe MSB of src1, wrap-around takes effect by taking index & (VL−1). Inrange addressing mode, when index is out of the VL−1 range, thedestination bit (in the destination vector) is zeroed. The destinationvector is masked based on the write mask.

FIG. 3 is a diagram illustrating a hardware processor that decodes andexecutes a strideshift instruction, according to some embodiments.Strideshift instruction 300 may be decoded by the decoder 102 andexecuted by the execution unit 104. Data may be accessed in register(s)106 and/or memory 110. The strideshift instruction 300 may take a firstinput vector and a second input vector as operands. The first inputvector is the vector to be transposed. The second input vector is thevector containing starting positions. The strideshift instruction 300may also take the stride as an operand. In one embodiment, the executionunit 104 executes the strideshift instruction 300 (e.g., vstrideshift)to cause the first input vector to be transposed with respect to themain diagonal ((0, 0)->(KL−1, KL−1)) and to cause the result to bestored as a destination vector. The transposition effectively takes bitscorresponding to a “row” in the first input vector and stores them asconsecutive bits in the destination vector to form a “column” in thedestination vector. In the example shown in the diagram, src1 is thefirst input vector, src2 is the second input vector, and dest is thedestination vector. For purposes of illustration, the specifics relatedto the transposition of “row” 2 of src1 is shown in the diagram. Itshould be understood that the other “rows” can be transposed in asimilar manner. In this example KL=7, VL=224, N=32, and stride=32. Sincethe value of the third element (element 2) of src2 is 2, the offset isset to 2. The index is calculated as offset+k*stride, where k=0 . . .31. The resulting index values (2, 34, 66, 98, . . . 482) correspond tothe bit positions in src1 that form “row” 2. The bits located at thesebit positions are stored as consecutive bits in “column” 2 of dest(since this is the “column” that corresponds to element 2 of src2). Inthis example, the strideshift instruction 300 uses range addressingmode. As such, when the index goes out of range (00R) (e.g., exceedsVL−1, which in this example is 223), the destination bit is zeroed.

In this way, the execution unit 104 may execute strideshift instruction300 to access a given bit of the first input vector located at a bitposition indicated by an element of the second input vector (e.g., thebit located at bit position 2) and stride over bits of the first inputvector using a stride (e.g., skips over every 32 bits) to access bits ofthe first input vector that are located at a strided bit position withrespect to the given bit (e.g., bits located at bit positions 34, 66, 98. . . ). The execution unit 104 may then store the given bit and thebits that are located at a strided position with respect to the givenbit as consecutive bits in a destination vector.

As previously mentioned, with the strideshift instruction, the followingsequence of instruction may be executed to determine the maximum andminimum values contained in an input vector zmm_index:

-   -   (1) zmm_sqr_conf=vconf_sqr_ge(zmm_index)    -   (2) k1=vpcmpeq(zmm_sqr_conf, zmm_cmp)    -   (3) zmm_max=vcompress(k1, zmm_index)    -   (4) zmm_transposed=vstrideshift(zmm_sqr_conf)    -   (5) k2=vpcmpeq(zmm_transposed, zmm_cmp)    -   (6) zmm_min=vcompress(k2, zmm_index)

In the above sequence of instructions, zmm_index is the vectorcontaining the values from which the maximum and minimum values are tobe determined. In the above sequence of instructions, zmm_cmp is apredefined (constant) vector containing a square matrix containing allbinary ‘1’s. In the above sequence of instructions, (1) is aninstruction to perform square all-to-all comparisons of the elements ofthe vector using a greater than or equal to comparison operation (e.g.,and stores the result as bit values, where a bit value of binary ‘1’indicates comparison is true and binary ‘0’ indicates otherwise). In theabove sequence of instructions, (2) is an instruction to perform vectorcomparison. In the above sequence of instructions, (3) is an instructionto perform vector compression. In the above sequence of instructions,(4) is a strideshift instruction (only the first operand is shown forpurposes of simplicity). In the above sequence of instructions, (5) isan instruction to perform vector comparison. In the above sequence ofinstructions, (6) is an instruction to perform vector compression.

FIG. 4 is a diagram illustrating a sequence of instructions beingexecuted to determine the minimum values contained in a vector,according to some embodiments. In the diagram, each vertical “column” isthe same lane of a vector register. The “offset” refers to the positionof an element. In this example, there are seven (KL=7) elements in avector. The values and sizes of the vectors are provided by way ofexample for purposes of illustration. It should be understood that othervalues and sizes may be utilized. In this example, zmm_index is thevector containing the values from which the minimum value is to bedetermined. In this example, zmm_index contains the values 5, 7, 1, 1,7, 3, and 1 (in order from LSB to MSB). Executing thevconf_sqr_ge(zmm_index) instruction produces zmm_sqr_conf. This may havealready been computed as part of determining the maximum value containedin zmm_index. In this example, zmm_start is the vector containingstarting positions (to be used by the vstrideshift instruction). In thisexample, zmm_start contains the values 0, 1, 2, 3, 4, 5, and 6 (in orderfrom LSB to MSB). Executing the vstrideshift(zmm_sqr_conf_ge, zmm_start,32) instruction produces zmm_transposed. In this example, zmm_cmp is apre-defined 7×7 matrix containing all binary ‘1’s. Executing thevpcmpeq(zmm_transposed, zmm_cmp) instruction produces k_mask_min, whichcontains binary ‘1’s in the bit position(s) corresponding to the minimumvalue. Executing the vcompress(k_mask_min, zmm_index) instructionproduces zmm_min, which contains the minimum value in its LSB lane (theminimum value is 1 in this example). In this way, the minimum valuecontained in zmm_index is determined without having to execute a secondsquare all-to-all comparison instruction (in addition to the squareall-to-all comparison instruction that was executed as part ofdetermining the maximum value).

FIG. 5 is a diagram illustrating the result of executing a strideshiftinstruction that uses a cyclic addressing mode, according to someembodiments. The diagram shows the vstridecshiftw(src1, src2, 32)instruction being executed. This instructions uses cyclic addressingmode (as indicated by the “c” in vstridecshiftw). In this example, src1contains data that is packed as double words and src2 contains startingpositions. Since data in src1 is packed as double words, the stride isset to 32. The write mask (e.g., k1) has word-level granularity to makethe data in destination to also be packed as double words (with 16meaningful lower bits corresponding to 16 rows in src1 and with 16 upperbits zeroed). The result of executing the vstridecshiftw(src1, src2, 32)instruction is stored in dest.

Since src2[12] contains a value of 136, the vstridecshiftw instructionstarts with accessing the bit of src1 located at bit position 136, whichis in “row” 8 and “column” 4 of src1. The vstridecshiftw instructionthen strides over the bits of src1 according to the specified stride toaccess the remaining bits in “row” 8. It should be noted that since thevstridecshiftw instruction uses cyclic addressing mode, wrap-aroundtakes effect after reaching bit position 488 to access bit positions 8,40, 72, and 104. The starting bit and the bits located at a strided bitposition with respect to the starting bit position are stored asconsecutive bits in “column” 12 of dest (since this “column” correspondsto the element of src2 that contained the starting position).

FIG. 6 is a flow diagram of a process for processing a strideshiftinstruction, according to some embodiments. The operations in the flowdiagrams will be described with reference to the exemplary embodimentsof the other figures. However, it should be understood that theoperations of the flow diagrams can be performed by embodiments otherthan those discussed with reference to the other figures, and theembodiments discussed with reference to these other figures can performoperations different than those discussed with reference to the flowdiagrams.

In one embodiment, the process is initiated when a decoder 102 (e.g.,decode circuit) decodes an instruction (e.g., a strideshift instruction)into a decoded instruction (block 610). An execution unit 104 (e.g.,execution circuit) executes the decoded instruction to access a firstbit of a first input vector located at a bit position indicated by anelement of a second input vector, stride over bits of the first inputvector using a stride to access bits of the first input vector that arelocated at a strided bit position with respect to the first bit of thefirst input vector, and store the first bit of the first input vectorand the bits of the first input vector that are located at a strided bitposition with respect to the first bit of the first input vector asconsecutive bits in a destination vector (block 620). In one embodiment,the execution circuit 104 is to determine a strided bit position withrespect to the first bit of the first input vector based on adding amultiple of the stride to the bit position of the first bit of the firstinput vector (e.g., index=(offset+k*stride)). In one embodiment, theexecution circuit 104 is to stride over bits of the first input vectorusing a cyclic addressing mode (wrap-around). In such an embodiment, theexecution circuit 104 may determine a strided bit position with respectto the first bit of the first input vector based on adding a multiple ofthe stride to the bit position of the first bit of the first inputvector to obtain an index and performing a modulo operation on the indexand a length of the destination vector in bits minus one (e.g., index &(VL−1)). In one embodiment, the execution circuit 104 is to stride overbits of the first input vector using a range addressing mode. In such anembodiment, the execution circuit 104 may store a binary ‘0’ in a bit ofthe destination vector in response to a determination that a strided bitposition with respect to the first bit of the first input vector is outof range (e.g., out of VL−1 range). In one embodiment, the consecutivebits in the destination register correspond to an element of thedestination vector and this element of the destination vectorcorresponds to the element of the second input vector that indicates thebit position of the first bit of the first input vector). In oneembodiment, the instruction specifies the stride. In one embodiment, theexecution circuit 104 is to mask bits of the destination vector using awrite mask.

Instruction Sets

An instruction set may include one or more instruction formats. A giveninstruction format may define various fields (e.g., number of bits,location of bits) to specify, among other things, the operation to beperformed (e.g., opcode) and the operand(s) on which that operation isto be performed and/or other data field(s) (e.g., mask). Someinstruction formats are further broken down though the definition ofinstruction templates (or subformats). For example, the instructiontemplates of a given instruction format may be defined to have differentsubsets of the instruction format's fields (the included fields aretypically in the same order, but at least some have different bitpositions because there are less fields included) and/or defined to havea given field interpreted differently. Thus, each instruction of an ISAis expressed using a given instruction format (and, if defined, in agiven one of the instruction templates of that instruction format) andincludes fields for specifying the operation and the operands. Forexample, an exemplary ADD instruction has a specific opcode and aninstruction format that includes an opcode field to specify that opcodeand operand fields to select operands (source1/destination and source2);and an occurrence of this ADD instruction in an instruction stream willhave specific contents in the operand fields that select specificoperands. A set of SIMD extensions referred to as the Advanced VectorExtensions (AVX) (AVX1 and AVX2) and using the Vector Extensions (VEX)coding scheme has been released and/or published (e.g., see Intel® 64and IA-32 Architectures Software Developer's Manual, September 2014; andsee Intel® Advanced Vector Extensions Programming Reference, October2014).

Exemplary Instruction Formats

Embodiments of the instruction(s) described herein may be embodied indifferent formats. Additionally, exemplary systems, architectures, andpipelines are detailed below. Embodiments of the instruction(s) may beexecuted on such systems, architectures, and pipelines, but are notlimited to those detailed.

Generic Vector Friendly Instruction Format

A vector friendly instruction format is an instruction format that issuited for vector instructions (e.g., there are certain fields specificto vector operations). While embodiments are described in which bothvector and scalar operations are supported through the vector friendlyinstruction format, alternative embodiments use only vector operationsthe vector friendly instruction format.

FIGS. 7A-7B are block diagrams illustrating a generic vector friendlyinstruction format and instruction templates thereof according toembodiments of the invention. FIG. 7A is a block diagram illustrating ageneric vector friendly instruction format and class A instructiontemplates thereof according to embodiments of the invention; while FIG.7B is a block diagram illustrating the generic vector friendlyinstruction format and class B instruction templates thereof accordingto embodiments of the invention. Specifically, a generic vector friendlyinstruction format 700 for which are defined class A and class Binstruction templates, both of which include no memory access 705instruction templates and memory access 720 instruction templates. Theterm generic in the context of the vector friendly instruction formatrefers to the instruction format not being tied to any specificinstruction set.

While embodiments of the invention will be described in which the vectorfriendly instruction format supports the following: a 64 byte vectoroperand length (or size) with 32 bit (4 byte) or 64 bit (8 byte) dataelement widths (or sizes) (and thus, a 64 byte vector consists of either16 doubleword-size elements or alternatively, 8 quadword-size elements);a 64 byte vector operand length (or size) with 16 bit (2 byte) or 8 bit(1 byte) data element widths (or sizes); a 32 byte vector operand length(or size) with 32 bit (4 byte), 64 bit (8 byte), 16 bit (2 byte), or 8bit (1 byte) data element widths (or sizes); and a 16 byte vectoroperand length (or size) with 32 bit (4 byte), 64 bit (8 byte), 16 bit(2 byte), or 8 bit (1 byte) data element widths (or sizes); alternativeembodiments may support more, less and/or different vector operand sizes(e.g., 256 byte vector operands) with more, less, or different dataelement widths (e.g., 128 bit (16 byte) data element widths).

The class A instruction templates in FIG. 7A include: 1) within the nomemory access 705 instruction templates there is shown a no memoryaccess, full round control type operation 710 instruction template and ano memory access, data transform type operation 715 instructiontemplate; and 2) within the memory access 720 instruction templatesthere is shown a memory access, temporal 725 instruction template and amemory access, non-temporal 730 instruction template. The class Binstruction templates in FIG. 7B include: 1) within the no memory access705 instruction templates there is shown a no memory access, write maskcontrol, partial round control type operation 712 instruction templateand a no memory access, write mask control, vsize type operation 717instruction template; and 2) within the memory access 720 instructiontemplates there is shown a memory access, write mask control 727instruction template.

The generic vector friendly instruction format 700 includes thefollowing fields listed below in the order illustrated in FIGS. 7A-7B.

Format field 740—a specific value (an instruction format identifiervalue) in this field uniquely identifies the vector friendly instructionformat, and thus occurrences of instructions in the vector friendlyinstruction format in instruction streams. As such, this field isoptional in the sense that it is not needed for an instruction set thathas only the generic vector friendly instruction format.

Base operation field 742—its content distinguishes different baseoperations.

Register index field 744—its content, directly or through addressgeneration, specifies the locations of the source and destinationoperands, be they in registers or in memory. These include a sufficientnumber of bits to select N registers from a P×Q (e.g. 32×512, 16×128,32×1024, 64×1024) register file. While in one embodiment N may be up tothree sources and one destination register, alternative embodiments maysupport more or less sources and destination registers (e.g., maysupport up to two sources where one of these sources also acts as thedestination, may support up to three sources where one of these sourcesalso acts as the destination, may support up to two sources and onedestination).

Modifier field 746—its content distinguishes occurrences of instructionsin the generic vector instruction format that specify memory access fromthose that do not; that is, between no memory access 705 instructiontemplates and memory access 720 instruction templates. Memory accessoperations read and/or write to the memory hierarchy (in some casesspecifying the source and/or destination addresses using values inregisters), while non-memory access operations do not (e.g., the sourceand destinations are registers). While in one embodiment this field alsoselects between three different ways to perform memory addresscalculations, alternative embodiments may support more, less, ordifferent ways to perform memory address calculations.

Augmentation operation field 750—its content distinguishes which one ofa variety of different operations to be performed in addition to thebase operation. This field is context specific. In one embodiment of theinvention, this field is divided into a class field 768, an alpha field752, and a beta field 754. The augmentation operation field 750 allowscommon groups of operations to be performed in a single instructionrather than 2, 3, or 4 instructions.

Scale field 760—its content allows for the scaling of the index field'scontent for memory address generation (e.g., for address generation thatuses 2^(scale)*index+base).

Displacement Field 762A—its content is used as part of memory addressgeneration (e.g., for address generation that uses2^(scale)*index+base+displacement).

Displacement Factor Field 762B (note that the juxtaposition ofdisplacement field 762A directly over displacement factor field 762Bindicates one or the other is used)—its content is used as part ofaddress generation; it specifies a displacement factor that is to bescaled by the size of a memory access (N)—where N is the number of bytesin the memory access (e.g., for address generation that uses2^(scale)*index+base+scaled displacement). Redundant low-order bits areignored and hence, the displacement factor field's content is multipliedby the memory operands total size (N) in order to generate the finaldisplacement to be used in calculating an effective address. The valueof N is determined by the processor hardware at runtime based on thefull opcode field 774 (described later herein) and the data manipulationfield 754C. The displacement field 762A and the displacement factorfield 762B are optional in the sense that they are not used for the nomemory access 705 instruction templates and/or different embodiments mayimplement only one or none of the two.

Data element width field 764—its content distinguishes which one of anumber of data element widths is to be used (in some embodiments for allinstructions; in other embodiments for only some of the instructions).This field is optional in the sense that it is not needed if only onedata element width is supported and/or data element widths are supportedusing some aspect of the opcodes.

Write mask field 770—its content controls, on a per data elementposition basis, whether that data element position in the destinationvector operand reflects the result of the base operation andaugmentation operation. Class A instruction templates supportmerging-writemasking, while class B instruction templates support bothmerging- and zeroing-writemasking. When merging, vector masks allow anyset of elements in the destination to be protected from updates duringthe execution of any operation (specified by the base operation and theaugmentation operation); in other one embodiment, preserving the oldvalue of each element of the destination where the corresponding maskbit has a 0. In contrast, when zeroing vector masks allow any set ofelements in the destination to be zeroed during the execution of anyoperation (specified by the base operation and the augmentationoperation); in one embodiment, an element of the destination is set to 0when the corresponding mask bit has a 0 value. A subset of thisfunctionality is the ability to control the vector length of theoperation being performed (that is, the span of elements being modified,from the first to the last one); however, it is not necessary that theelements that are modified be consecutive. Thus, the write mask field770 allows for partial vector operations, including loads, stores,arithmetic, logical, etc. While embodiments of the invention aredescribed in which the write mask field's 770 content selects one of anumber of write mask registers that contains the write mask to be used(and thus the write mask field's 770 content indirectly identifies thatmasking to be performed), alternative embodiments instead or additionalallow the mask write field's 770 content to directly specify the maskingto be performed.

Immediate field 772—its content allows for the specification of animmediate. This field is optional in the sense that is it not present inan implementation of the generic vector friendly format that does notsupport immediate and it is not present in instructions that do not usean immediate.

Class field 768—its content distinguishes between different classes ofinstructions. With reference to FIGS. 7A-B, the contents of this fieldselect between class A and class B instructions. In FIGS. 7A-B, roundedcorner squares are used to indicate a specific value is present in afield (e.g., class A 768A and class B 768B for the class field 768respectively in FIGS. 7A-B).

Instruction Templates of Class A

In the case of the non-memory access 705 instruction templates of classA, the alpha field 752 is interpreted as an RS field 752A, whose contentdistinguishes which one of the different augmentation operation typesare to be performed (e.g., round 752A.1 and data transform 752A.2 arerespectively specified for the no memory access, round type operation710 and the no memory access, data transform type operation 715instruction templates), while the beta field 754 distinguishes which ofthe operations of the specified type is to be performed. In the nomemory access 705 instruction templates, the scale field 760, thedisplacement field 762A, and the displacement scale filed 762B are notpresent.

No-Memory Access Instruction Templates—Full Round Control Type Operation

In the no memory access full round control type operation 710instruction template, the beta field 754 is interpreted as a roundcontrol field 754A, whose content(s) provide static rounding. While inthe described embodiments of the invention the round control field 754Aincludes a suppress all floating point exceptions (SAE) field 756 and around operation control field 758, alternative embodiments may supportmay encode both these concepts into the same field or only have one orthe other of these concepts/fields (e.g., may have only the roundoperation control field 758).

SAE field 756—its content distinguishes whether or not to disable theexception event reporting; when the SAE field's 756 content indicatessuppression is enabled, a given instruction does not report any kind offloating-point exception flag and does not raise any floating pointexception handler.

Round operation control field 758—its content distinguishes which one ofa group of rounding operations to perform (e.g., Round-up, Round-down,Round-towards-zero and Round-to-nearest). Thus, the round operationcontrol field 758 allows for the changing of the rounding mode on a perinstruction basis. In one embodiment of the invention where a processorincludes a control register for specifying rounding modes, the roundoperation control field's 750 content overrides that register value.

No Memory Access Instruction Templates—Data Transform Type Operation

In the no memory access data transform type operation 715 instructiontemplate, the beta field 754 is interpreted as a data transform field754B, whose content distinguishes which one of a number of datatransforms is to be performed (e.g., no data transform, swizzle,broadcast).

In the case of a memory access 720 instruction template of class A, thealpha field 752 is interpreted as an eviction hint field 752B, whosecontent distinguishes which one of the eviction hints is to be used (inFIG. 7A, temporal 752B.1 and non-temporal 752B.2 are respectivelyspecified for the memory access, temporal 725 instruction template andthe memory access, non-temporal 730 instruction template), while thebeta field 754 is interpreted as a data manipulation field 754C, whosecontent distinguishes which one of a number of data manipulationoperations (also known as primitives) is to be performed (e.g., nomanipulation; broadcast; up conversion of a source; and down conversionof a destination). The memory access 720 instruction templates includethe scale field 760, and optionally the displacement field 762A or thedisplacement scale field 762B.

Vector memory instructions perform vector loads from and vector storesto memory, with conversion support. As with regular vector instructions,vector memory instructions transfer data from/to memory in a dataelement-wise fashion, with the elements that are actually transferred isdictated by the contents of the vector mask that is selected as thewrite mask.

Memory Access Instruction Templates—Temporal

Temporal data is data likely to be reused soon enough to benefit fromcaching. This is, however, a hint, and different processors mayimplement it in different ways, including ignoring the hint entirely.

Memory Access Instruction Templates—Non-Temporal

Non-temporal data is data unlikely to be reused soon enough to benefitfrom caching in the 1st-level cache and should be given priority foreviction. This is, however, a hint, and different processors mayimplement it in different ways, including ignoring the hint entirely.

Instruction Templates of Class B

In the case of the instruction templates of class B, the alpha field 752is interpreted as a write mask control (Z) field 752C, whose contentdistinguishes whether the write masking controlled by the write maskfield 770 should be a merging or a zeroing.

In the case of the non-memory access 705 instruction templates of classB, part of the beta field 754 is interpreted as an RL field 757A, whosecontent distinguishes which one of the different augmentation operationtypes are to be performed (e.g., round 757A.1 and vector length (VSIZE)757A.2 are respectively specified for the no memory access, write maskcontrol, partial round control type operation 712 instruction templateand the no memory access, write mask control, VSIZE type operation 717instruction template), while the rest of the beta field 754distinguishes which of the operations of the specified type is to beperformed. In the no memory access 705 instruction templates, the scalefield 760, the displacement field 762A, and the displacement scale filed762B are not present.

In the no memory access, write mask control, partial round control typeoperation 710 instruction template, the rest of the beta field 754 isinterpreted as a round operation field 759A and exception eventreporting is disabled (a given instruction does not report any kind offloating-point exception flag and does not raise any floating pointexception handler).

Round operation control field 759A—just as round operation control field758, its content distinguishes which one of a group of roundingoperations to perform (e.g., Round-up, Round-down, Round-towards-zeroand Round-to-nearest). Thus, the round operation control field 759Aallows for the changing of the rounding mode on a per instruction basis.In one embodiment of the invention where a processor includes a controlregister for specifying rounding modes, the round operation controlfield's 750 content overrides that register value.

In the no memory access, write mask control, VSIZE type operation 717instruction template, the rest of the beta field 754 is interpreted as avector length field 759B, whose content distinguishes which one of anumber of data vector lengths is to be performed on (e.g., 128, 256, or512 byte).

In the case of a memory access 720 instruction template of class B, partof the beta field 754 is interpreted as a broadcast field 757B, whosecontent distinguishes whether or not the broadcast type datamanipulation operation is to be performed, while the rest of the betafield 754 is interpreted the vector length field 759B. The memory access720 instruction templates include the scale field 760, and optionallythe displacement field 762A or the displacement scale field 762B.

With regard to the generic vector friendly instruction format 700, afull opcode field 774 is shown including the format field 740, the baseoperation field 742, and the data element width field 764. While oneembodiment is shown where the full opcode field 774 includes all ofthese fields, the full opcode field 774 includes less than all of thesefields in embodiments that do not support all of them. The full opcodefield 774 provides the operation code (opcode).

The augmentation operation field 750, the data element width field 764,and the write mask field 770 allow these features to be specified on aper instruction basis in the generic vector friendly instruction format.

The combination of write mask field and data element width field createtyped instructions in that they allow the mask to be applied based ondifferent data element widths.

The various instruction templates found within class A and class B arebeneficial in different situations. In some embodiments of theinvention, different processors or different cores within a processormay support only class A, only class B, or both classes. For instance, ahigh performance general purpose out-of-order core intended forgeneral-purpose computing may support only class B, a core intendedprimarily for graphics and/or scientific (throughput) computing maysupport only class A, and a core intended for both may support both (ofcourse, a core that has some mix of templates and instructions from bothclasses but not all templates and instructions from both classes iswithin the purview of the invention). Also, a single processor mayinclude multiple cores, all of which support the same class or in whichdifferent cores support different class. For instance, in a processorwith separate graphics and general purpose cores, one of the graphicscores intended primarily for graphics and/or scientific computing maysupport only class A, while one or more of the general purpose cores maybe high performance general purpose cores with out of order executionand register renaming intended for general-purpose computing thatsupport only class B. Another processor that does not have a separategraphics core, may include one more general purpose in-order orout-of-order cores that support both class A and class B. Of course,features from one class may also be implement in the other class indifferent embodiments of the invention. Programs written in a high levellanguage would be put (e.g., just in time compiled or staticallycompiled) into an variety of different executable forms, including: 1) aform having only instructions of the class(es) supported by the targetprocessor for execution; or 2) a form having alternative routineswritten using different combinations of the instructions of all classesand having control flow code that selects the routines to execute basedon the instructions supported by the processor which is currentlyexecuting the code.

Exemplary Specific Vector Friendly Instruction Format

FIG. 8A is a block diagram illustrating an exemplary specific vectorfriendly instruction format according to embodiments of the invention.FIG. 8A shows a specific vector friendly instruction format 800 that isspecific in the sense that it specifies the location, size,interpretation, and order of the fields, as well as values for some ofthose fields. The specific vector friendly instruction format 800 may beused to extend the x86 instruction set, and thus some of the fields aresimilar or the same as those used in the existing x86 instruction setand extension thereof (e.g., AVX). This format remains consistent withthe prefix encoding field, real opcode byte field, MOD R/M field, SIBfield, displacement field, and immediate fields of the existing x86instruction set with extensions. The fields from FIG. 7 into which thefields from FIG. 8A map are illustrated.

It should be understood that, although embodiments of the invention aredescribed with reference to the specific vector friendly instructionformat 800 in the context of the generic vector friendly instructionformat 700 for illustrative purposes, the invention is not limited tothe specific vector friendly instruction format 800 except whereclaimed. For example, the generic vector friendly instruction format 700contemplates a variety of possible sizes for the various fields, whilethe specific vector friendly instruction format 800 is shown as havingfields of specific sizes. By way of specific example, while the dataelement width field 764 is illustrated as a one bit field in thespecific vector friendly instruction format 800, the invention is not solimited (that is, the generic vector friendly instruction format 700contemplates other sizes of the data element width field 764).

The generic vector friendly instruction format 700 includes thefollowing fields listed below in the order illustrated in FIG. 8A.

EVEX Prefix (Bytes 0-3) 802—is encoded in a four-byte form.

Format Field 740 (EVEX Byte 0, bits [7:0])—the first byte (EVEX Byte 0)is the format field 740 and it contains 0x62 (the unique value used fordistinguishing the vector friendly instruction format in one embodimentof the invention).

The second-fourth bytes (EVEX Bytes 1-3) include a number of bit fieldsproviding specific capability.

REX field 805 (EVEX Byte 1, bits [7-5])—consists of a EVEX.R bit field(EVEX Byte 1, bit [7]—R), EVEX.X bit field (EVEX byte 1, bit [6]—X), and757BEX byte 1, bit[5]—B). The EVEX.R, EVEX.X, and EVEX.B bit fieldsprovide the same functionality as the corresponding VEX bit fields, andare encoded using 1s complement form, i.e. ZMM0 is encoded as 1111B,ZMM15 is encoded as 0000B. Other fields of the instructions encode thelower three bits of the register indexes as is known in the art (rrr,xxx, and bbb), so that Rrrr, Xxxx, and Bbbb may be formed by addingEVEX.R, EVEX.X, and EVEX.B.

REX′ field 710—this is the first part of the REX′ field 710 and is theEVEX.R′ bit field (EVEX Byte 1, bit [4]—R′) that is used to encodeeither the upper 16 or lower 16 of the extended 32 register set. In oneembodiment of the invention, this bit, along with others as indicatedbelow, is stored in bit inverted format to distinguish (in thewell-known x86 32-bit mode) from the BOUND instruction, whose realopcode byte is 62, but does not accept in the MOD R/M field (describedbelow) the value of 11 in the MOD field; alternative embodiments of theinvention do not store this and the other indicated bits below in theinverted format. A value of 1 is used to encode the lower 16 registers.In other words, R′Rrrr is formed by combining EVEX.R′, EVEX.R, and theother RRR from other fields.

Opcode map field 815 (EVEX byte 1, bits [3:0]—mmmm)—its content encodesan implied leading opcode byte (0F, 0F 38, or 0F 3).

Data element width field 764 (EVEX byte 2, bit [7]—W)—is represented bythe notation EVEX.W. EVEX.W is used to define the granularity (size) ofthe datatype (either 32-bit data elements or 64-bit data elements).

EVEX.vvvv 820 (EVEX Byte 2, bits [6:3]—vvvv)—the role of EVEX.vvvv mayinclude the following: 1) EVEX.vvvv encodes the first source registeroperand, specified in inverted (1s complement) form and is valid forinstructions with 2 or more source operands; 2) EVEX.vvvv encodes thedestination register operand, specified in 1s complement form forcertain vector shifts; or 3) EVEX.vvvv does not encode any operand, thefield is reserved and should contain 1111b. Thus, EVEX.vvvv field 820encodes the 4 low-order bits of the first source register specifierstored in inverted (1s complement) form. Depending on the instruction,an extra different EVEX bit field is used to extend the specifier sizeto 32 registers.

EVEX.U 768 Class field (EVEX byte 2, bit [2]—U)—If EVEX.U=0, itindicates class A or EVEX.U0; if EVEX.U=1, it indicates class B orEVEX.U1.

Prefix encoding field 825 (EVEX byte 2, bits [1:0]—pp)—providesadditional bits for the base operation field. In addition to providingsupport for the legacy SSE instructions in the EVEX prefix format, thisalso has the benefit of compacting the SIMD prefix (rather thanrequiring a byte to express the SIMD prefix, the EVEX prefix requiresonly 2 bits). In one embodiment, to support legacy SSE instructions thatuse a SIMD prefix (66H, F2H, F3H) in both the legacy format and in theEVEX prefix format, these legacy SIMD prefixes are encoded into the SIMDprefix encoding field; and at runtime are expanded into the legacy SIMDprefix prior to being provided to the decoder's PLA (so the PLA canexecute both the legacy and EVEX format of these legacy instructionswithout modification). Although newer instructions could use the EVEXprefix encoding field's content directly as an opcode extension, certainembodiments expand in a similar fashion for consistency but allow fordifferent meanings to be specified by these legacy SIMD prefixes. Analternative embodiment may redesign the PLA to support the 2 bit SIMDprefix encodings, and thus not require the expansion.

Alpha field 752 (EVEX byte 3, bit [7]—EH; also known as EVEX.EH,EVEX.rs, EVEX.RL, EVEX.write mask control, and EVEX.N; also illustratedwith a)—as previously described, this field is context specific.

Beta field 754 (EVEX byte 3, bits [6:4]—SSS, also known as EVEX.s₂₋₀,EVEX.r₂₋₀, EVEX.rr1, EVEX.LL0, EVEX.LLB; also illustrated with βββ)—aspreviously described, this field is context specific.

REX′ field 710—this is the remainder of the REX′ field and is theEVEX.V′ bit field (EVEX Byte 3, bit [3]—V′) that may be used to encodeeither the upper 16 or lower 16 of the extended 32 register set. Thisbit is stored in bit inverted format. A value of 1 is used to encode thelower 16 registers. In other words, V′VVVV is formed by combiningEVEX.V′, EVEX.vvvv.

Write mask field 770 (EVEX byte 3, bits [2:0]—kkk)—its content specifiesthe index of a register in the write mask registers as previouslydescribed. In one embodiment of the invention, the specific valueEVEX.kkk=000 has a special behavior implying no write mask is used forthe particular instruction (this may be implemented in a variety of waysincluding the use of a write mask hardwired to all ones or hardware thatbypasses the masking hardware).

Real Opcode Field 830 (Byte 4) is also known as the opcode byte. Part ofthe opcode is specified in this field.

MOD R/M Field 840 (Byte 5) includes MOD field 842, Reg field 844, andR/M field 846. As previously described, the MOD field's 842 contentdistinguishes between memory access and non-memory access operations.The role of Reg field 844 can be summarized to two situations: encodingeither the destination register operand or a source register operand, orbe treated as an opcode extension and not used to encode any instructionoperand. The role of R/M field 846 may include the following: encodingthe instruction operand that references a memory address, or encodingeither the destination register operand or a source register operand.

Scale, Index, Base (SIB) Byte (Byte 6)—As previously described, thescale field's 750 content is used for memory address generation. SIB.xxx854 and SIB.bbb 856—the contents of these fields have been previouslyreferred to with regard to the register indexes Xxxx and Bbbb.

Displacement field 762A (Bytes 7-10)—when MOD field 842 contains 10,bytes 7-10 are the displacement field 762A, and it works the same as thelegacy 32-bit displacement (disp32) and works at byte granularity.

Displacement factor field 762B (Byte 7)—when MOD field 842 contains 01,byte 7 is the displacement factor field 762B. The location of this fieldis that same as that of the legacy x86 instruction set 8-bitdisplacement (disp8), which works at byte granularity. Since disp8 issign extended, it can only address between −128 and 127 bytes offsets;in terms of 64 byte cache lines, disp8 uses 8 bits that can be set toonly four really useful values −128, −64, 0, and 64; since a greaterrange is often needed, disp32 is used; however, disp32 requires 4 bytes.In contrast to disp8 and disp32, the displacement factor field 762B is areinterpretation of disp8; when using displacement factor field 762B,the actual displacement is determined by the content of the displacementfactor field multiplied by the size of the memory operand access (N).This type of displacement is referred to as disp8*N. This reduces theaverage instruction length (a single byte of used for the displacementbut with a much greater range). Such compressed displacement is based onthe assumption that the effective displacement is multiple of thegranularity of the memory access, and hence, the redundant low-orderbits of the address offset do not need to be encoded. In other words,the displacement factor field 762B substitutes the legacy x86instruction set 8-bit displacement. Thus, the displacement factor field762B is encoded the same way as an x86 instruction set 8-bitdisplacement (so no changes in the ModRM/SIB encoding rules) with theonly exception that disp8 is overloaded to disp8*N. In other words,there are no changes in the encoding rules or encoding lengths but onlyin the interpretation of the displacement value by hardware (which needsto scale the displacement by the size of the memory operand to obtain abyte-wise address offset). Immediate field 772 operates as previouslydescribed.

Full Opcode Field

FIG. 8B is a block diagram illustrating the fields of the specificvector friendly instruction format 800 that make up the full opcodefield 774 according to one embodiment of the invention. Specifically,the full opcode field 774 includes the format field 740, the baseoperation field 742, and the data element width (W) field 764. The baseoperation field 742 includes the prefix encoding field 825, the opcodemap field 815, and the real opcode field 830.

Register Index Field

FIG. 8C is a block diagram illustrating the fields of the specificvector friendly instruction format 800 that make up the register indexfield 744 according to one embodiment of the invention. Specifically,the register index field 744 includes the REX field 805, the REX′ field810, the MODR/M.reg field 844, the MODR/M.r/m field 846, the VVVV field820, xxx field 854, and the bbb field 856.

Augmentation Operation Field

FIG. 8D is a block diagram illustrating the fields of the specificvector friendly instruction format 800 that make up the augmentationoperation field 750 according to one embodiment of the invention. Whenthe class (U) field 768 contains 0, it signifies EVEX.U0 (class A 768A);when it contains 1, it signifies EVEX.U1(class B 768B). When U=0 and theMOD field 842 contains 11 (signifying a no memory access operation), thealpha field 752 (EVEX byte 3, bit [7]—EH) is interpreted as the rs field752A. When the rs field 752A contains a 1 (round 752A.1), the beta field754 (EVEX byte 3, bits [6:4]—SSS) is interpreted as the round controlfield 754A. The round control field 754A includes a one bit SAE field756 and a two bit round operation field 758. When the rs field 752Acontains a 0 (data transform 752A.2), the beta field 754 (EVEX byte 3,bits [6:4]—SSS) is interpreted as a three bit data transform field 754B.When U=0 and the MOD field 842 contains 00, 01, or 10 (signifying amemory access operation), the alpha field 752 (EVEX byte 3, bit [7]—EH)is interpreted as the eviction hint (EH) field 752B and the beta field754 (EVEX byte 3, bits [6:4]—SSS) is interpreted as a three bit datamanipulation field 754C.

When U=1, the alpha field 752 (EVEX byte 3, bit [7]—EH) is interpretedas the write mask control (Z) field 752C. When U=1 and the MOD field 842contains 11 (signifying a no memory access operation), part of the betafield 754 (EVEX byte 3, bit [4]—S₀) is interpreted as the RL field 757A;when it contains a 1 (round 757A.1) the rest of the beta field 754 (EVEXbyte 3, bit [6-5]—S₂₋₁) is interpreted as the round operation field759A, while when the RL field 757A contains a 0 (VSIZE 757.A2) the restof the beta field 754 (EVEX byte 3, bit [6-5]—S₂₋₁) is interpreted asthe vector length field 759B (EVEX byte 3, bit [6-5]—L₁₋₀). When U=1 andthe MOD field 842 contains 00, 01, or 10 (signifying a memory accessoperation), the beta field 754 (EVEX byte 3, bits [6:4]—SSS) isinterpreted as the vector length field 759B (EVEX byte 3, bit[6-5]—L₁₋₀) and the broadcast field 757B (EVEX byte 3, bit [4]—B).

Exemplary Register Architecture

FIG. 9 is a block diagram of a register architecture 900 according toone embodiment of the invention. In the embodiment illustrated, thereare 32 vector registers 910 that are 512 bits wide; these registers arereferenced as zmm0 through zmm31. The lower order 256 bits of the lower16 zmm registers are overlaid on registers ymm0-16. The lower order 128bits of the lower 16 zmm registers (the lower order 128 bits of the ymmregisters) are overlaid on registers xmm0-15. The specific vectorfriendly instruction format 800 operates on these overlaid register fileas illustrated in the below tables.

Adjustable Vector Opera- Length Class tions Registers InstructionTemplates A 710, 715, zmm registers (the vector that do not include(FIG. 7A; 725, 730 length is 64 byte) the vector length U = 0) field759B B 712 zmm registers (the vector (FIG. 7B; length is 64 byte) U = 1)Instruction templates B 717, 727 zmm, ymm, or xmm that do include the(FIG. 7B; registers (the vector vector length field U = 1) length is 64byte, 32 759B byte, or 16 byte) depending on the vector length field759B

In other words, the vector length field 759B selects between a maximumlength and one or more other shorter lengths, where each such shorterlength is half the length of the preceding length; and instructionstemplates without the vector length field 759B operate on the maximumvector length. Further, in one embodiment, the class B instructiontemplates of the specific vector friendly instruction format 800 operateon packed or scalar single/double-precision floating point data andpacked or scalar integer data. Scalar operations are operationsperformed on the lowest order data element position in an zmm/ymm/xmmregister; the higher order data element positions are either left thesame as they were prior to the instruction or zeroed depending on theembodiment.

Write mask registers 915—in the embodiment illustrated, there are 8write mask registers (k0 through k7), each 64 bits in size. In analternate embodiment, the write mask registers 915 are 16 bits in size.As previously described, in one embodiment of the invention, the vectormask register k0 cannot be used as a write mask; when the encoding thatwould normally indicate k0 is used for a write mask, it selects ahardwired write mask of 0xFFFF, effectively disabling write masking forthat instruction.

General-purpose registers 925—in the embodiment illustrated, there aresixteen 64-bit general-purpose registers that are used along with theexisting x86 addressing modes to address memory operands. Theseregisters are referenced by the names RAX, RBX, RCX, RDX, RBP, RSI, RDI,RSP, and R8 through R15.

Scalar floating point stack register file (x87 stack) 945, on which isaliased the MMX packed integer flat register file 950—in the embodimentillustrated, the x87 stack is an eight-element stack used to performscalar floating-point operations on 32/64/80-bit floating point datausing the x87 instruction set extension; while the MMX registers areused to perform operations on 64-bit packed integer data, as well as tohold operands for some operations performed between the MMX and XMMregisters.

Alternative embodiments of the invention may use wider or narrowerregisters. Additionally, alternative embodiments of the invention mayuse more, less, or different register files and registers.

Exemplary Core Architectures, Processors, and Computer Architectures

Processor cores may be implemented in different ways, for differentpurposes, and in different processors. For instance, implementations ofsuch cores may include: 1) a general purpose in-order core intended forgeneral-purpose computing; 2) a high performance general purposeout-of-order core intended for general-purpose computing; 3) a specialpurpose core intended primarily for graphics and/or scientific(throughput) computing. Implementations of different processors mayinclude: 1) a CPU including one or more general purpose in-order coresintended for general-purpose computing and/or one or more generalpurpose out-of-order cores intended for general-purpose computing; and2) a coprocessor including one or more special purpose cores intendedprimarily for graphics and/or scientific (throughput). Such differentprocessors lead to different computer system architectures, which mayinclude: 1) the coprocessor on a separate chip from the CPU; 2) thecoprocessor on a separate die in the same package as a CPU; 3) thecoprocessor on the same die as a CPU (in which case, such a coprocessoris sometimes referred to as special purpose logic, such as integratedgraphics and/or scientific (throughput) logic, or as special purposecores); and 4) a system on a chip that may include on the same die thedescribed CPU (sometimes referred to as the application core(s) orapplication processor(s)), the above described coprocessor, andadditional functionality. Exemplary core architectures are describednext, followed by descriptions of exemplary processors and computerarchitectures.

Exemplary Core Architectures In-Order and Out-of-Order Core BlockDiagram

FIG. 10A is a block diagram illustrating both an exemplary in-orderpipeline and an exemplary register renaming, out-of-orderissue/execution pipeline according to embodiments of the invention. FIG.10B is a block diagram illustrating both an exemplary embodiment of anin-order architecture core and an exemplary register renaming,out-of-order issue/execution architecture core to be included in aprocessor according to embodiments of the invention. The solid linedboxes in FIGS. 10A-B illustrate the in-order pipeline and in-order core,while the optional addition of the dashed lined boxes illustrates theregister renaming, out-of-order issue/execution pipeline and core. Giventhat the in-order aspect is a subset of the out-of-order aspect, theout-of-order aspect will be described.

In FIG. 10A, a processor pipeline 1000 includes a fetch stage 1002, alength decode stage 1004, a decode stage 1006, an allocation stage 1008,a renaming stage 1010, a scheduling (also known as a dispatch or issue)stage 1012, a register read/memory read stage 1014, an execute stage1016, a write back/memory write stage 1018, an exception handling stage1022, and a commit stage 1024.

FIG. 10B shows processor core 1090 including a front end unit 1030coupled to an execution engine unit 1050, and both are coupled to amemory unit 1070. The core 1090 may be a reduced instruction setcomputing (RISC) core, a complex instruction set computing (CISC) core,a very long instruction word (VLIW) core, or a hybrid or alternativecore type. As yet another option, the core 1090 may be a special-purposecore, such as, for example, a network or communication core, compressionengine, coprocessor core, general purpose computing graphics processingunit (GPGPU) core, graphics core, or the like.

The front end unit 1030 includes a branch prediction unit 1032 coupledto an instruction cache unit 1034, which is coupled to an instructiontranslation lookaside buffer (TLB) 1036, which is coupled to aninstruction fetch unit 1038, which is coupled to a decode unit 1040. Thedecode unit 1040 (or decoder) may decode instructions, and generate asan output one or more micro-operations, micro-code entry points,microinstructions, other instructions, or other control signals, whichare decoded from, or which otherwise reflect, or are derived from, theoriginal instructions. The decode unit 1040 may be implemented usingvarious different mechanisms. Examples of suitable mechanisms include,but are not limited to, look-up tables, hardware implementations,programmable logic arrays (PLAs), microcode read only memories (ROMs),etc. In one embodiment, the core 1090 includes a microcode ROM or othermedium that stores microcode for certain macroinstructions (e.g., indecode unit 1040 or otherwise within the front end unit 1030). Thedecode unit 1040 is coupled to a rename/allocator unit 1052 in theexecution engine unit 1050.

The execution engine unit 1050 includes the rename/allocator unit 1052coupled to a retirement unit 1054 and a set of one or more schedulerunit(s) 1056. The scheduler unit(s) 1056 represents any number ofdifferent schedulers, including reservations stations, centralinstruction window, etc. The scheduler unit(s) 1056 is coupled to thephysical register file(s) unit(s) 1058. Each of the physical registerfile(s) units 1058 represents one or more physical register files,different ones of which store one or more different data types, such asscalar integer, scalar floating point, packed integer, packed floatingpoint, vector integer, vector floating point, status (e.g., aninstruction pointer that is the address of the next instruction to beexecuted), etc. In one embodiment, the physical register file(s) unit1058 comprises a vector registers unit, a write mask registers unit, anda scalar registers unit. These register units may provide architecturalvector registers, vector mask registers, and general purpose registers.The physical register file(s) unit(s) 1058 is overlapped by theretirement unit 1054 to illustrate various ways in which registerrenaming and out-of-order execution may be implemented (e.g., using areorder buffer(s) and a retirement register file(s); using a futurefile(s), a history buffer(s), and a retirement register file(s); using aregister maps and a pool of registers; etc.). The retirement unit 1054and the physical register file(s) unit(s) 1058 are coupled to theexecution cluster(s) 1060. The execution cluster(s) 1060 includes a setof one or more execution units 1062 and a set of one or more memoryaccess units 1064. The execution units 1062 may perform variousoperations (e.g., shifts, addition, subtraction, multiplication) and onvarious types of data (e.g., scalar floating point, packed integer,packed floating point, vector integer, vector floating point). Whilesome embodiments may include a number of execution units dedicated tospecific functions or sets of functions, other embodiments may includeonly one execution unit or multiple execution units that all perform allfunctions. The scheduler unit(s) 1056, physical register file(s) unit(s)1058, and execution cluster(s) 1060 are shown as being possibly pluralbecause certain embodiments create separate pipelines for certain typesof data/operations (e.g., a scalar integer pipeline, a scalar floatingpoint/packed integer/packed floating point/vector integer/vectorfloating point pipeline, and/or a memory access pipeline that each havetheir own scheduler unit, physical register file(s) unit, and/orexecution cluster—and in the case of a separate memory access pipeline,certain embodiments are implemented in which only the execution clusterof this pipeline has the memory access unit(s) 1064). It should also beunderstood that where separate pipelines are used, one or more of thesepipelines may be out-of-order issue/execution and the rest in-order.

The set of memory access units 1064 is coupled to the memory unit 1070,which includes a data TLB unit 1072 coupled to a data cache unit 1074coupled to a level 2 (L2) cache unit 1076. In one exemplary embodiment,the memory access units 1064 may include a load unit, a store addressunit, and a store data unit, each of which is coupled to the data TLBunit 1072 in the memory unit 1070. The instruction cache unit 1034 isfurther coupled to a level 2 (L2) cache unit 1076 in the memory unit1070. The L2 cache unit 1076 is coupled to one or more other levels ofcache and eventually to a main memory.

By way of example, the exemplary register renaming, out-of-orderissue/execution core architecture may implement the pipeline 1000 asfollows: 1) the instruction fetch 1038 performs the fetch and lengthdecoding stages 1002 and 1004; 2) the decode unit 1040 performs thedecode stage 1006; 3) the rename/allocator unit 1052 performs theallocation stage 1008 and renaming stage 1010; 4) the scheduler unit(s)1056 performs the schedule stage 1012; 5) the physical register file(s)unit(s) 1058 and the memory unit 1070 perform the register read/memoryread stage 1014; the execution cluster 1060 perform the execute stage1016; 6) the memory unit 1070 and the physical register file(s) unit(s)1058 perform the write back/memory write stage 1018; 7) various unitsmay be involved in the exception handling stage 1022; and 8) theretirement unit 1054 and the physical register file(s) unit(s) 1058perform the commit stage 1024.

The core 1090 may support one or more instructions sets (e.g., the x86instruction set (with some extensions that have been added with newerversions); the MIPS instruction set of MIPS Technologies of Sunnyvale,Calif.; the ARM instruction set (with optional additional extensionssuch as NEON) of ARM Holdings of Sunnyvale, Calif.), including theinstruction(s) described herein. In one embodiment, the core 1090includes logic to support a packed data instruction set extension (e.g.,AVX1, AVX2), thereby allowing the operations used by many multimediaapplications to be performed using packed data.

It should be understood that the core may support multithreading(executing two or more parallel sets of operations or threads), and maydo so in a variety of ways including time sliced multithreading,simultaneous multithreading (where a single physical core provides alogical core for each of the threads that physical core issimultaneously multithreading), or a combination thereof (e.g., timesliced fetching and decoding and simultaneous multithreading thereaftersuch as in the Intel® Hyperthreading technology).

While register renaming is described in the context of out-of-orderexecution, it should be understood that register renaming may be used inan in-order architecture. While the illustrated embodiment of theprocessor also includes separate instruction and data cache units1034/1074 and a shared L2 cache unit 1076, alternative embodiments mayhave a single internal cache for both instructions and data, such as,for example, a Level 1 (L1) internal cache, or multiple levels ofinternal cache. In some embodiments, the system may include acombination of an internal cache and an external cache that is externalto the core and/or the processor. Alternatively, all of the cache may beexternal to the core and/or the processor.

Specific Exemplary in-Order Core Architecture

FIGS. 11A-B illustrate a block diagram of a more specific exemplaryin-order core architecture, which core would be one of several logicblocks (including other cores of the same type and/or different types)in a chip. The logic blocks communicate through a high-bandwidthinterconnect network (e.g., a ring network) with some fixed functionlogic, memory I/O interfaces, and other necessary I/O logic, dependingon the application.

FIG. 11A is a block diagram of a single processor core, along with itsconnection to the on-die interconnect network 1102 and with its localsubset of the Level 2 (L2) cache 1104, according to embodiments of theinvention. In one embodiment, an instruction decoder 1100 supports thex86 instruction set with a packed data instruction set extension. An L1cache 1106 allows low-latency accesses to cache memory into the scalarand vector units. While in one embodiment (to simplify the design), ascalar unit 1108 and a vector unit 1110 use separate register sets(respectively, scalar registers 1112 and vector registers 1114) and datatransferred between them is written to memory and then read back in froma level 1 (L1) cache 1106, alternative embodiments of the invention mayuse a different approach (e.g., use a single register set or include acommunication path that allow data to be transferred between the tworegister files without being written and read back).

The local subset of the L2 cache 1104 is part of a global L2 cache thatis divided into separate local subsets, one per processor core. Eachprocessor core has a direct access path to its own local subset of theL2 cache 1104. Data read by a processor core is stored in its L2 cachesubset 1104 and can be accessed quickly, in parallel with otherprocessor cores accessing their own local L2 cache subsets. Data writtenby a processor core is stored in its own L2 cache subset 1104 and isflushed from other subsets, if necessary. The ring network ensurescoherency for shared data. The ring network is bi-directional to allowagents such as processor cores, L2 caches and other logic blocks tocommunicate with each other within the chip. Each ring data-path is1012-bits wide per direction.

FIG. 11B is an expanded view of part of the processor core in FIG. 11Aaccording to embodiments of the invention. FIG. 11B includes an L1 datacache 1106A part of the L1 cache 1104, as well as more detail regardingthe vector unit 1110 and the vector registers 1114. Specifically, thevector unit 1110 is a 16-wide vector processing unit (VPU) (see the16-wide ALU 1128), which executes one or more of integer,single-precision float, and double-precision float instructions. The VPUsupports swizzling the register inputs with swizzle unit 1120, numericconversion with numeric convert units 1122A-B, and replication withreplication unit 1124 on the memory input. Write mask registers 1126allow predicating resulting vector writes.

FIG. 12 is a block diagram of a processor 1200 that may have more thanone core, may have an integrated memory controller, and may haveintegrated graphics according to embodiments of the invention. The solidlined boxes in FIG. 12 illustrate a processor 1200 with a single core1202A, a system agent 1210, a set of one or more bus controller units1216, while the optional addition of the dashed lined boxes illustratesan alternative processor 1200 with multiple cores 1202A-N, a set of oneor more integrated memory controller unit(s) 1214 in the system agentunit 1210, and special purpose logic 1208.

Thus, different implementations of the processor 1200 may include: 1) aCPU with the special purpose logic 1208 being integrated graphics and/orscientific (throughput) logic (which may include one or more cores), andthe cores 1202A-N being one or more general purpose cores (e.g., generalpurpose in-order cores, general purpose out-of-order cores, acombination of the two); 2) a coprocessor with the cores 1202A-N being alarge number of special purpose cores intended primarily for graphicsand/or scientific (throughput); and 3) a coprocessor with the cores1202A-N being a large number of general purpose in-order cores. Thus,the processor 1200 may be a general-purpose processor, coprocessor orspecial-purpose processor, such as, for example, a network orcommunication processor, compression engine, graphics processor, GPGPU(general purpose graphics processing unit), a high-throughput manyintegrated core (MIC) coprocessor (including 30 or more cores), embeddedprocessor, or the like. The processor may be implemented on one or morechips. The processor 1200 may be a part of and/or may be implemented onone or more substrates using any of a number of process technologies,such as, for example, BiCMOS, CMOS, or NMOS.

The memory hierarchy includes one or more levels of cache within thecores, a set or one or more shared cache units 1206, and external memory(not shown) coupled to the set of integrated memory controller units1214. The set of shared cache units 1206 may include one or moremid-level caches, such as level 2 (L2), level 3 (L3), level 4 (L4), orother levels of cache, a last level cache (LLC), and/or combinationsthereof. While in one embodiment a ring based interconnect unit 1212interconnects the integrated graphics logic 1208 (integrated graphicslogic 1208 is an example of and is also referred to herein as specialpurpose logic), the set of shared cache units 1206, and the system agentunit 1210/integrated memory controller unit(s) 1214, alternativeembodiments may use any number of well-known techniques forinterconnecting such units. In one embodiment, coherency is maintainedbetween one or more cache units 1206 and cores 1202-A-N.

In some embodiments, one or more of the cores 1202A-N are capable ofmulti-threading. The system agent 1210 includes those componentscoordinating and operating cores 1202A-N. The system agent unit 1210 mayinclude for example a power control unit (PCU) and a display unit. ThePCU may be or include logic and components needed for regulating thepower state of the cores 1202A-N and the integrated graphics logic 1208.The display unit is for driving one or more externally connecteddisplays.

The cores 1202A-N may be homogenous or heterogeneous in terms ofarchitecture instruction set; that is, two or more of the cores 1202A-Nmay be capable of execution the same instruction set, while others maybe capable of executing only a subset of that instruction set or adifferent instruction set.

Exemplary Computer Architectures

FIGS. 13-16 are block diagrams of exemplary computer architectures.Other system designs and configurations known in the arts for laptops,desktops, handheld PCs, personal digital assistants, engineeringworkstations, servers, network devices, network hubs, switches, embeddedprocessors, digital signal processors (DSPs), graphics devices, videogame devices, set-top boxes, micro controllers, cell phones, portablemedia players, hand held devices, and various other electronic devices,are also suitable. In general, a huge variety of systems or electronicdevices capable of incorporating a processor and/or other executionlogic as disclosed herein are generally suitable.

Referring now to FIG. 13, shown is a block diagram of a system 1300 inaccordance with one embodiment of the present invention. The system 1300may include one or more processors 1310, 1315, which are coupled to acontroller hub 1320. In one embodiment the controller hub 1320 includesa graphics memory controller hub (GMCH) 1390 and an Input/Output Hub(IOH) 1350 (which may be on separate chips); the GMCH 1390 includesmemory and graphics controllers to which are coupled memory 1340 and acoprocessor 1345; the IOH 1350 couples input/output (I/O) devices 1360to the GMCH 1390. Alternatively, one or both of the memory and graphicscontrollers are integrated within the processor (as described herein),the memory 1340 and the coprocessor 1345 are coupled directly to theprocessor 1310, and the controller hub 1320 in a single chip with theIOH 1350.

The optional nature of additional processors 1315 is denoted in FIG. 13with broken lines. Each processor 1310, 1315 may include one or more ofthe processing cores described herein and may be some version of theprocessor 1200.

The memory 1340 may be, for example, dynamic random access memory(DRAM), phase change memory (PCM), or a combination of the two. For atleast one embodiment, the controller hub 1320 communicates with theprocessor(s) 1310, 1315 via a multi-drop bus, such as a frontside bus(FSB), point-to-point interface such as QuickPath Interconnect (QPI), orsimilar connection 1395.

In one embodiment, the coprocessor 1345 is a special-purpose processor,such as, for example, a high-throughput MIC processor, a network orcommunication processor, compression engine, graphics processor, GPGPU,embedded processor, or the like. In one embodiment, controller hub 1320may include an integrated graphics accelerator.

There can be a variety of differences between the physical resources1310, 1315 in terms of a spectrum of metrics of merit includingarchitectural, microarchitectural, thermal, power consumptioncharacteristics, and the like.

In one embodiment, the processor 1310 executes instructions that controldata processing operations of a general type. Embedded within theinstructions may be coprocessor instructions. The processor 1310recognizes these coprocessor instructions as being of a type that shouldbe executed by the attached coprocessor 1345. Accordingly, the processor1310 issues these coprocessor instructions (or control signalsrepresenting coprocessor instructions) on a coprocessor bus or otherinterconnect, to coprocessor 1345. Coprocessor(s) 1345 accept andexecute the received coprocessor instructions.

Referring now to FIG. 14, shown is a block diagram of a first morespecific exemplary system 1400 in accordance with an embodiment of thepresent invention. As shown in FIG. 14, multiprocessor system 1400 is apoint-to-point interconnect system, and includes a first processor 1470and a second processor 1480 coupled via a point-to-point interconnect1450. Each of processors 1470 and 1480 may be some version of theprocessor 1200. In one embodiment of the invention, processors 1470 and1480 are respectively processors 1310 and 1315, while coprocessor 1438is coprocessor 1345. In another embodiment, processors 1470 and 1480 arerespectively processor 1310 coprocessor 1345.

Processors 1470 and 1480 are shown including integrated memorycontroller (IMC) units 1472 and 1482, respectively. Processor 1470 alsoincludes as part of its bus controller units point-to-point (P-P)interfaces 1476 and 1478; similarly, second processor 1480 includes P-Pinterfaces 1486 and 1488. Processors 1470, 1480 may exchange informationvia a point-to-point (P-P) interface 1450 using P-P interface circuits1478, 1488. As shown in FIG. 14, IMCs 1472 and 1482 couple theprocessors to respective memories, namely a memory 1432 and a memory1434, which may be portions of main memory locally attached to therespective processors.

Processors 1470, 1480 may each exchange information with a chipset 1490via individual P-P interfaces 1452, 1454 using point to point interfacecircuits 1476, 1494, 1486, 1498. Chipset 1490 may optionally exchangeinformation with the coprocessor 1438 via a high-performance interface1492. In one embodiment, the coprocessor 1438 is a special-purposeprocessor, such as, for example, a high-throughput MIC processor, anetwork or communication processor, compression engine, graphicsprocessor, GPGPU, embedded processor, or the like.

A shared cache (not shown) may be included in either processor oroutside of both processors, yet connected with the processors via P-Pinterconnect, such that either or both processors' local cacheinformation may be stored in the shared cache if a processor is placedinto a low power mode.

Chipset 1490 may be coupled to a first bus 1416 via an interface 1496.In one embodiment, first bus 1416 may be a Peripheral ComponentInterconnect (PCI) bus, or a bus such as a PCI Express bus or anotherthird generation I/O interconnect bus, although the scope of the presentinvention is not so limited.

As shown in FIG. 14, various I/O devices 1414 may be coupled to firstbus 1416, along with a bus bridge 1418 which couples first bus 1416 to asecond bus 1420. In one embodiment, one or more additional processor(s)1415, such as coprocessors, high-throughput MIC processors, GPGPU's,accelerators (such as, e.g., graphics accelerators or digital signalprocessing (DSP) units), field programmable gate arrays, or any otherprocessor, are coupled to first bus 1416. In one embodiment, second bus1420 may be a low pin count (LPC) bus. Various devices may be coupled toa second bus 1420 including, for example, a keyboard and/or mouse 1422,communication devices 1427 and a storage unit 1428 such as a disk driveor other mass storage device which may include instructions/code anddata 1430, in one embodiment. Further, an audio I/O 1424 may be coupledto the second bus 1420. Note that other architectures are possible. Forexample, instead of the point-to-point architecture of FIG. 14, a systemmay implement a multi-drop bus or other such architecture.

Referring now to FIG. 15, shown is a block diagram of a second morespecific exemplary system 1500 in accordance with an embodiment of thepresent invention. Like elements in FIGS. 14 and 15 bear like referencenumerals, and certain aspects of FIG. 14 have been omitted from FIG. 15in order to avoid obscuring other aspects of FIG. 15.

FIG. 15 illustrates that the processors 1470, 1480 may includeintegrated memory and I/O control logic (“CL”) 1472 and 1482,respectively. Thus, the CL 1472, 1482 include integrated memorycontroller units and include I/O control logic. FIG. 15 illustrates thatnot only are the memories 1432, 1434 coupled to the CL 1472, 1482, butalso that I/O devices 1514 are also coupled to the control logic 1472,1482. Legacy I/O devices 1515 are coupled to the chipset 1490.

Referring now to FIG. 16, shown is a block diagram of a SoC 1600 inaccordance with an embodiment of the present invention. Similar elementsin FIG. 12 bear like reference numerals. Also, dashed lined boxes areoptional features on more advanced SoCs. In FIG. 16, an interconnectunit(s) 1602 is coupled to: an application processor 1610 which includesa set of one or more cores 1202A-N, which include cache units 1204A-N,and shared cache unit(s) 1206; a system agent unit 1210; a buscontroller unit(s) 1216; an integrated memory controller unit(s) 1214; aset or one or more coprocessors 1620 which may include integratedgraphics logic, an image processor, an audio processor, and a videoprocessor; an static random access memory (SRAM) unit 1630; a directmemory access (DMA) unit 1632; and a display unit 1640 for coupling toone or more external displays. In one embodiment, the coprocessor(s)1620 include a special-purpose processor, such as, for example, anetwork or communication processor, compression engine, GPGPU, ahigh-throughput MIC processor, embedded processor, or the like.

Embodiments of the mechanisms disclosed herein may be implemented inhardware, software, firmware, or a combination of such implementationapproaches. Embodiments of the invention may be implemented as computerprograms or program code executing on programmable systems comprising atleast one processor, a storage system (including volatile andnon-volatile memory and/or storage elements), at least one input device,and at least one output device.

Program code, such as code 1430 illustrated in FIG. 14, may be appliedto input instructions to perform the functions described herein andgenerate output information. The output information may be applied toone or more output devices, in known fashion. For purposes of thisapplication, a processing system includes any system that has aprocessor, such as, for example; a digital signal processor (DSP), amicrocontroller, an application specific integrated circuit (ASIC), or amicroprocessor.

The program code may be implemented in a high level procedural or objectoriented programming language to communicate with a processing system.The program code may also be implemented in assembly or machinelanguage, if desired. In fact, the mechanisms described herein are notlimited in scope to any particular programming language. In any case,the language may be a compiled or interpreted language.

One or more aspects of at least one embodiment may be implemented byrepresentative instructions stored on a machine-readable medium whichrepresents various logic within the processor, which when read by amachine causes the machine to fabricate logic to perform the techniquesdescribed herein. Such representations, known as “IP cores” may bestored on a tangible, machine readable medium and supplied to variouscustomers or manufacturing facilities to load into the fabricationmachines that actually make the logic or processor.

Such machine-readable storage media may include, without limitation,non-transitory, tangible arrangements of articles manufactured or formedby a machine or device, including storage media such as hard disks, anyother type of disk including floppy disks, optical disks, compact diskread-only memories (CD-ROMs), compact disk rewritable's (CD-RWs), andmagneto-optical disks, semiconductor devices such as read-only memories(ROMs), random access memories (RAMs) such as dynamic random accessmemories (DRAMs), static random access memories (SRAMs), erasableprogrammable read-only memories (EPROMs), flash memories, electricallyerasable programmable read-only memories (EEPROMs), phase change memory(PCM), magnetic or optical cards, or any other type of media suitablefor storing electronic instructions.

Accordingly, embodiments of the invention also include non-transitory,tangible machine-readable media containing instructions or containingdesign data, such as Hardware Description Language (HDL), which definesstructures, circuits, apparatuses, processors and/or system featuresdescribed herein. Such embodiments may also be referred to as programproducts.

Emulation (Including Binary Translation, Code Morphing, Etc.)

In some cases, an instruction converter may be used to convert aninstruction from a source instruction set to a target instruction set.For example, the instruction converter may translate (e.g., using staticbinary translation, dynamic binary translation including dynamiccompilation), morph, emulate, or otherwise convert an instruction to oneor more other instructions to be processed by the core. The instructionconverter may be implemented in software, hardware, firmware, or acombination thereof. The instruction converter may be on processor, offprocessor, or part on and part off processor.

FIG. 17 is a block diagram contrasting the use of a software instructionconverter to convert binary instructions in a source instruction set tobinary instructions in a target instruction set according to embodimentsof the invention. In the illustrated embodiment, the instructionconverter is a software instruction converter, although alternativelythe instruction converter may be implemented in software, firmware,hardware, or various combinations thereof. FIG. 17 shows a program in ahigh level language 1702 may be compiled using an x86 compiler 1704 togenerate x86 binary code 1706 that may be natively executed by aprocessor with at least one x86 instruction set core 1716. The processorwith at least one x86 instruction set core 1716 represents any processorthat can perform substantially the same functions as an Intel processorwith at least one x86 instruction set core by compatibly executing orotherwise processing (1) a substantial portion of the instruction set ofthe Intel x86 instruction set core or (2) object code versions ofapplications or other software targeted to run on an Intel processorwith at least one x86 instruction set core, in order to achievesubstantially the same result as an Intel processor with at least onex86 instruction set core. The x86 compiler 1704 represents a compilerthat is operable to generate x86 binary code 1706 (e.g., object code)that can, with or without additional linkage processing, be executed onthe processor with at least one x86 instruction set core 1716.Similarly, FIG. 17 shows the program in the high level language 1702 maybe compiled using an alternative instruction set compiler 1708 togenerate alternative instruction set binary code 1710 that may benatively executed by a processor without at least one x86 instructionset core 1714 (e.g., a processor with cores that execute the MIPSinstruction set of MIPS Technologies of Sunnyvale, Calif. and/or thatexecute the ARM instruction set of ARM Holdings of Sunnyvale, Calif.).The instruction converter 1712 is used to convert the x86 binary code1706 into code that may be natively executed by the processor without anx86 instruction set core 1714. This converted code is not likely to bethe same as the alternative instruction set binary code 1710 because aninstruction converter capable of this is difficult to make; however, theconverted code will accomplish the general operation and be made up ofinstructions from the alternative instruction set. Thus, the instructionconverter 1712 represents software, firmware, hardware, or a combinationthereof that, through emulation, simulation or any other process, allowsa processor or other electronic device that does not have an x86instruction set processor or core to execute the x86 binary code 1706.

Examples

Example 1 is a processor. The processor includes a decode circuit todecode an instruction into a decoded instruction and an executioncircuit to execute the decoded instruction to access a first bit of afirst input vector located at a bit position indicated by an element ofa second input vector, stride over bits of the first input vector usinga stride to access bits of the first input vector that are located at astrided bit position with respect to the first bit of the first inputvector, and store the first bit of the first input vector and the bitsof the first input vector that are located at a strided bit positionwith respect to the first bit of the first input vector as consecutivebits in a destination vector.

Example 2 includes the substance of example 1. In this example, theexecution circuit is to determine a strided bit position with respect tothe first bit of the first input vector based on adding a multiple ofthe stride to the bit position of the first bit of the first inputvector.

Example 3 includes the substance of example 1. In this example, theexecution circuit is to stride over bits of the first input vector usingthe stride using a cyclic addressing mode.

Example 4 includes the substance of example 3. In this example, theexecution circuit is to determine a strided bit position with respect tothe first bit of the first input vector based on adding a multiple ofthe stride to the bit position of the first bit of the first inputvector to obtain an index and performing a modulo operation on the indexand a length of the destination vector in bits minus one.

Example 5 includes the substance of example 1. In this example, theexecution circuit is to stride over bits of the first input vector usinga range addressing mode.

Example 6 includes the substance of example 5. In this example, theexecution circuit is to store a binary ‘0’ in a bit of the destinationvector in response to a determination that a strided bit position withrespect to the first bit of the first input vector is out of range.

Example 7 includes the substance of example 1. In this example, theconsecutive bits in the destination vector correspond to an element ofthe destination vector, and the element of the destination vectorcorresponds to the element of the second input vector.

Example 8 includes the substance of example 1. In this example, theinstruction specifies the stride.

Example 9 includes the substance of example 1. In this example, theexecution circuit is to mask bits of the destination vector using awrite mask.

Example 10 is a method performed by a processor. The method includesdecoding an instruction into a decoded instruction and executing thedecoded instruction to access a first bit of a first input vectorlocated at a bit position indicated by an element of a second inputvector, stride over bits of the first input vector using a stride toaccess bits of the first input vector that are located at a strided bitposition with respect to the first bit of the first input vector, andstore the first bit of the first input vector and the bits of the firstinput vector that are located at a strided bit position with respect tothe first bit of the first input vector as consecutive bits in adestination vector.

Example 11 includes the substance of example 10. In this example, theexecution is to determine a strided bit position with respect to thefirst bit of the first input vector based on adding a multiple of thestride to the bit position of the first bit of the first input vector.

Example 12 includes the substance of example 10. In this example, theexecution is to stride over bits of the first input vector using thestride using a cyclic addressing mode.

Example 13 includes the substance of example 12. In this example, theexecution is to determine a strided bit position with respect to thefirst bit of the first input vector based on adding a multiple of thestride to the bit position of the first bit of the first input vector toobtain an index and performing a modulo operation on the index and alength of the destination vector in bits minus one.

Example 14 includes the substance of example 10. In this example,execution is to stride over bits of the first input vector using a rangeaddressing mode.

Example 15 includes the substance of example 14. In this example, theexecution is to store a binary ‘0’ in a bit of the destination vector inresponse to a determination that a strided bit position with respect tothe first bit of the first input vector is out of range.

Example 16 includes the substance of example 10. In this example, theconsecutive bits in the destination vector correspond to an element ofthe destination vector, and where the element of the destination vectorcorresponds to the element of the second input vector.

Example 17 includes the substance of example 10. In this example, theinstruction specifies the stride.

Example 18 includes the substance of example 10. In this example, theexecution is to mask bits of the destination vector using a write mask.

Example 19 is a non-transitory machine readable medium. Thenon-transitory machine readable medium has instruction stored therein,which when executed by a processor, causes the processor to decode aninstruction into a decoded instruction and execute the decodedinstruction to access a first bit of a first input vector located at abit position indicated by an element of a second input vector, strideover bits of the first input vector using a stride to access bits of thefirst input vector that are located at a strided bit position withrespect to the first bit of the first input vector, and store the firstbit of the first input vector and the bits of the first input vectorthat are located at a strided bit position with respect to the first bitof the first input vector as consecutive bits in a destination vector.

Example 20 includes the substance of example 19. In this example, theexecution is to determine a strided bit position with respect to thefirst bit of the first input vector based on adding a multiple of thestride to the bit position of the first bit of the first input vector.

Example 21 includes the substance of example 19. In this example, theexecution is to stride over bits of the first input vector using thestride using a cyclic addressing mode.

Example 22 includes the substance of example 21. In this example, theexecution is to determine a strided bit position with respect to thefirst bit of the first input vector based on adding a multiple of thestride to the bit position of the first bit of the first input vector toobtain an index and performing a modulo operation on the index and alength of the destination vector in bits minus one.

Example 23 includes the substance of example 19. In this example, theexecution is to stride over bits of the first input vector using a rangeaddressing mode.

Example 24 includes the substance of example 23. In this example, theexecution is to store a binary ‘0’ in a bit of the destination vector inresponse to a determination that a strided bit position with respect tothe first bit of the first input vector is out of range.

Example 25 includes the substance of example 19. In this example, theconsecutive bits in the destination vector correspond to an element ofthe destination vector, and where the element of the destination vectorcorresponds to the element of the second input vector.

Example 26 includes the substance of example 19. In this example, theinstruction specifies the stride.

Example 27 includes the substance of example 19. In this example, theexecution is to mask bits of the destination vector using a write mask.

Example 28 is a hardware processor. The hardware processor includes adecoding means to decode an instruction into a decoded instruction andan executing means to execute the decoded instruction to access a firstbit of a first input vector located at a bit position indicated by anelement of a second input vector, stride over bits of the first inputvector using a stride to access bits of the first input vector that arelocated at a strided bit position with respect to the first bit of thefirst input vector, and store the first bit of the first input vectorand the bits of the first input vector that are located at a strided bitposition with respect to the first bit of the first input vector asconsecutive bits in a destination vector.

Example 29 includes the substance of example 28. In this example, theexecuting means is to determine a strided bit position with respect tothe first bit of the first input vector based on adding a multiple ofthe stride to the bit position of the first bit of the first inputvector.

Example 30 includes the substance of example 28. In this example, theexecuting means is to stride over bits of the first input vector usingthe stride using a cyclic addressing mode.

Example 31 includes the substance of example 30. In this example, theexecuting means is to determine a strided bit position with respect tothe first bit of the first input vector based on adding a multiple ofthe stride to the bit position of the first bit of the first inputvector to obtain an index and performing a modulo operation on the indexand a length of the destination vector in bits minus one.

Example 32 includes the substance of example 28. In this example, theexecuting means is to stride over bits of the first input vector using arange addressing mode.

Example 33 includes the substance of example 32. In this example, theexecuting means is to store a binary ‘0’ in a bit of the destinationvector in response to a determination that a strided bit position withrespect to the first bit of the first input vector is out of range.

Example 34 includes the substance of example 28. In this example, theconsecutive bits in the destination vector correspond to an element ofthe destination vector, and where the element of the destination vectorcorresponds to the element of the second input vector.

Example 35 includes the substance of example 28. In this example, theinstruction specifies the stride.

Example 36 includes the substance of example 28. In this example, theexecuting means is to mask bits of the destination vector using a writemask.

Example 37 is a system for executing instructions. The system includes amemory and a processor coupled to the memory. The processor includes adecode circuit to decode an instruction into a decoded instruction andan execution circuit to execute the decoded instruction to access afirst bit of a first input vector located at a bit position indicated byan element of a second input vector, stride over bits of the first inputvector using a stride to access bits of the first input vector that arelocated at a strided bit position with respect to the first bit of thefirst input vector, and store the first bit of the first input vectorand the bits of the first input vector that are located at a strided bitposition with respect to the first bit of the first input vector asconsecutive bits in a destination vector.

Example 38 includes the substance of example 37. In this example, theexecution circuit is to determine a strided bit position with respect tothe first bit of the first input vector based on adding a multiple ofthe stride to the bit position of the first bit of the first inputvector.

While the invention has been described in terms of several embodiments,those skilled in the art will recognize that the invention is notlimited to the embodiments described, can be practiced with modificationand alteration within the spirit and scope of the appended claims. Thedescription is thus to be regarded as illustrative instead of limiting.

1. A processor comprising: a decode circuit to decode an instructioninto a decoded instruction; and an execution circuit to execute thedecoded instruction to: access a first bit of a first input vectorlocated at a bit position indicated by an element of a second inputvector, stride over bits of the first input vector using a stride toaccess bits of the first input vector that are located at a strided bitposition with respect to the first bit of the first input vector, andstore the first bit of the first input vector and the bits of the firstinput vector that are located at a strided bit position with respect tothe first bit of the first input vector as consecutive bits in adestination vector.
 2. The processor of claim 1, wherein the executioncircuit is to determine a strided bit position with respect to the firstbit of the first input vector based on adding a multiple of the strideto the bit position of the first bit of the first input vector.
 3. Theprocessor of claim 1, wherein the execution circuit is to stride overbits of the first input vector using the stride using a cyclicaddressing mode.
 4. The processor of claim 3, wherein the executioncircuit is to determine a strided bit position with respect to the firstbit of the first input vector based on adding a multiple of the strideto the bit position of the first bit of the first input vector to obtainan index and performing a modulo operation on the index and a length ofthe destination vector in bits minus one.
 5. The processor of claim 1,wherein the execution circuit is to stride over bits of the first inputvector using a range addressing mode.
 6. The processor of claim 5,wherein the execution circuit is to store a binary ‘0’ in a bit of thedestination vector in response to a determination that a strided bitposition with respect to the first bit of the first input vector is outof range.
 7. The processor of claim 1, wherein the consecutive bits inthe destination vector correspond to an element of the destinationvector, and wherein the element of the destination vector corresponds tothe element of the second input vector.
 8. The processor of claim 1,wherein the instruction specifies the stride.
 9. The processor of claim1, wherein the execution circuit is to mask bits of the destinationvector using a write mask.
 10. A method performed by a processorcomprising: decoding an instruction into a decoded instruction; andexecuting the decoded instruction to access a first bit of a first inputvector located at a bit position indicated by an element of a secondinput vector, stride over bits of the first input vector using a strideto access bits of the first input vector that are located at a stridedbit position with respect to the first bit of the first input vector,and store the first bit of the first input vector and the bits of thefirst input vector that are located at a strided bit position withrespect to the first bit of the first input vector as consecutive bitsin a destination vector.
 11. The method of claim 10, wherein theexecution is to determine a strided bit position with respect to thefirst bit of the first input vector based on adding a multiple of thestride to the bit position of the first bit of the first input vector.12. The method of claim 10, wherein the execution is to stride over bitsof the first input vector using the stride using a cyclic addressingmode.
 13. The method of claim 12, wherein the execution is to determinea strided bit position with respect to the first bit of the first inputvector based on adding a multiple of the stride to the bit position ofthe first bit of the first input vector to obtain an index andperforming a modulo operation on the index and a length of thedestination vector in bits minus one.
 14. The method of claim 10,wherein the execution is to stride over bits of the first input vectorusing a range addressing mode.
 15. The method of claim 14, wherein theexecution is to store a binary ‘0’ in a bit of the destination vector inresponse to a determination that a strided bit position with respect tothe first bit of the first input vector is out of range.
 16. Anon-transitory machine readable medium having stored thereininstructions, which when executed by a processor, causes the processorto: decode an instruction into a decoded instruction; and execute thedecoded instruction to access a first bit of a first input vectorlocated at a bit position indicated by an element of a second inputvector, stride over bits of the first input vector using a stride toaccess bits of the first input vector that are located at a strided bitposition with respect to the first bit of the first input vector, andstore the first bit of the first input vector and the bits of the firstinput vector that are located at a strided bit position with respect tothe first bit of the first input vector as consecutive bits in adestination vector.
 17. The non-transitory machine readable medium ofclaim 16, wherein the execution is to determine a strided bit positionwith respect to the first bit of the first input vector based on addinga multiple of the stride to the bit position of the first bit of thefirst input vector.
 18. The non-transitory machine readable medium ofclaim 16, wherein the execution is to stride over bits of the firstinput vector using the stride using a cyclic addressing mode.
 19. Thenon-transitory machine readable medium of claim 16, wherein theexecution is to stride over bits of the first input vector using a rangeaddressing mode.
 20. The non-transitory machine readable medium of claim16, wherein the consecutive bits in the destination vector correspond toan element of the destination vector, and wherein the element of thedestination vector corresponds to the element of the second inputvector.
 21. The non-transitory machine readable medium of claim 16,wherein the instruction specifies the stride.
 22. (canceled) 23.(canceled)
 24. (canceled)
 25. (canceled)